The goal of the proposed studies is to investigate the relationships between binge consumption of palatable food, diet-induced obesity risk, and brain endocannabinoid systems. Experiments proposed under Specific Aim 1 will test the hypothesis that the risk of developing binge-like consumption of palatable foods and the risk of developing diet-induced obesity are independent. The tendency of selectively-bred obesity-prone vs. obesity-resistant rat lines to "binge" will be evaluated using a behavioral paradigm in which limiting access to a highly palatable food precipitates rapid and excessive food intake when the palatable option becomes available. The impact of limited vs. continuous access to a palatable, high fat diet on consummatory, endocrine, and morphometric endpoints will be compared across lines to identify potential interactions between the availability of palatable food and genetic obesity risk. Specific Aim 2 will use biochemical and pharmacological approaches to test the hypothesis that central endocannabinoid systems are functionally involved in both binge eating and diet-induced obesity. By comparing alterations in endocannabinoid signaling associated with limited vs continous palatable food access in obesity-prone and obesity-resistant subjects, these experiments can reveal specific features related to diet-induced obesity risk, to high fat diet exposure per se, or to the obesity that can result from a high fat diet. The experiments will employ molecular analysis of mRNA and protein expression levels in discrete brain regions, biochemical analysis of tissue endocannabinoid content, and behavioral analysis of sensitivity to the central anorectic effects of cannabinoid antagonists. Experiments under Specific Aim 1 and Specific Aim 2 will form the core of the applicant's training plan in conceptual and methodological approaches to obesity-related research. Under the guidance of Dr. Eric Zorrilla, the applicant will develop skills in molecular pharmacology and behavioral neuroscience in preparation for a research career in neuropharmacology. Relevance: Obesity is a widespread public health problem that would benefit from the identification of molecular markers associated with increased risk. This project will deepen current understanding of the involvement of the endocannabinoid system in obesity risk and disodered eating.